This invention relates to molded composite racquets having the combination of graphite fibers surrounded by fiberglass layers in a bias orientation.
Heretofore, the use of racquets has multiplied according to the introduction of new racquet sports. Likewise, the kind of material used to form the frame of each type of racquet has been expanded according to the particular requirements of the recreational activity. Racquet sports, such as tennis, squash, racquetball, badminton and others have benefited from the use of various alloys of metal, including aluminum, magnesium, titanium, and steel. As well as other composite material design concepts and wood. However, in the case of wood and metals, because of the relative densities of the materials previously used, sacrifice of strength and stiffness of material was necessitated by the reduction of excess weight. Therefore, an improvement to the strength control of stiffness, and a reduction in the weight, of the frame is achieved by various resinous composites, either of the thermoplastic or the thermosetting plastic type. U.S. Pat. No. 3,981,504 discloses a composite racquet which uses a resinous material reinforced by various, random fibrous material. However, resolution of the various stresses applied to the racquet during recreation are not maximized under this construction. Other racquet constructions have attempted to resolve stresses by modifications to composite type, quantity and orientation. For example, U.S. Pat. No. 3,755,037 teaches a composite racquet construction having a fluid filled interior. U.S. Pat. No. 3,787,051 teaches a tennis racquet entirely made from resin impregnated glass fibers continuously oriented with the hoop of the head of the racquet. Further, U.S. Pat. No. 3,840,230 discloses a multi-layered racquet having a synthetic resin interior and two fiber-reinforced plastic outside layers. U.S. Pat. No. 3,483,055 discloses a racquet having flexible, windable materials cured on a form.
It has been found that the stress resolution for racquets required more than the introduction of resinous material and fiberglass to the construction of the frame, for the distribution of flexibility and mass requirements are not adequately controlled by these constructions. Therefore, a need exists for the preparation of a composite racquet which reduces the weight of the frame, more optimally resolves the physical stresses in the frame during use, controls the flexibility distribution and controls the mass distribution.